Ssimplify the function implemention and error handling
by invoking a lambda coroutine on shard 0 that keeps
a gate holder and semaphore units on its stack, for RAII-
style unwinding.
It then may invoke a function on another shard, using
the peered service container() to do the
replay on the destination shard.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
85d0bbb4fc